1. Field of the Invention
The present invention relates to drainage and ventilation tubes for the middle ear, and particularly to a middle ear ventilation tube having auxiliary openings for preventing clogging of the tube.
2. Description of the Related Art
The installation of tubes in the tympanic membrane, which separates the middle ear from the outer ear, is a well-known remedy for treating inflammation of the middle ear, or otitis media. Typically, a myringotomy is performed to create an opening in the tympanic membrane, and a vent or drain in the form of a tube is inserted into the opening to permit drainage of fluid from the middle ear to alleviate a buildup or reduction of pressure in the middle ear cavity. The tube functions to maintain the opening in the tympanic membrane for a sufficient period of time following the surgery to allow pressure to equalize between the middle and outer ears. Frequently, the condition of buildup or reduction of pressure in the middle ear cavity, which the tube is intended to alleviate, requires that the tube remain in place for a significant period of time, ranging in duration from about six to about twenty-four months.
A variety of ventilation tubes for insertion into an opening in the tympanic membrane have been used over the years. Typical conventional ventilation tubes are generally cylindrical, which allows the tubes to be easily inserted into the myringotomy opening, but are susceptible to accidental extraction from the tympanic membrane. On the other hand, ventilation tubes having anchoring structures are also known and are less likely to be accidentally extracted from the tympanic membrane, but are difficult to insert into, and extract from, the myringotomy openings, tending to enlarge the myringotomy openings such that the tendency of the tubes to fall out of the membrane increases. Thus, although some anchoring is necessary, minimizing the size of the structure is desirable.
Further, typical ventilation tubes suffer from clogging, particularly with extended use. The clogging is often caused by epithelial migration, occlusion by middle ear effusions, or simple buildup of cerumen (i.e., ear wax). The problem of displacement, as described above, can also cause one end of the tube to become at least partially covered and closed off.
The prevention of such clogging and dislodgment of the tube is necessary, since subsequent infection within the ear will cause a pressure build-up of pus and wax behind the tympanic membrane if the middle ear cannot be drained, which, along with dislodging the tube, presents the risk of possibly tearing the membrane as the tube is pushed against or through the tympanic membrane.
Thus, a middle ear ventilation tube solving the aforementioned problems is desired.